1. Field of the Invention
The invention relates to hull shapes for ships and submarines that substantially eliminate waves caused by movement in or on the water.
2. Description of the Related Art
A traditional hull that is found in the prior art has a pointed end at the bow, and a blunt transom at the stern. When moving forward through the water, the bow generates a bow wave and the stern generates a stern wave and a transverse wave. The vessel also generates pressure waves directed downward. Transverse waves are generated by both sharp and blunt-end sterns.
Generating these waves requires displacing large masses of water, does not assist with the efficiency or the sea-worthiness of the vessel, and wastes a great deal of energy. These waves also present a hazard to other vessels, and can be a source of danger or discomfort to their crews and passengers. One example is an accident that occurred in August, 1999, in the Cape Cod Canal. The admiralty court found that the accident was caused by the large waves generated by a passing ship. The accident caused US $1.3 million in damage. Large waves also greatly contribute to bank and channel erosion, and weaken bridge and pier supports. It is apparent that a vessel hull that reduces or eliminates bow, stern, and transverse waves would be very beneficial.
Others have attempted to modify the hull design to reduce or eliminate waves. One of them is U.S. Pat. No. 6,112,687 (the '687 patent), which is not admitted to being prior art by its mention in this Background section. In this patent, a “displacement body” is disposed on the underside of the hull and shaped to cancel the waves the hull would otherwise make. This hull does not take pressure waves generated in the downward direction into account at all, and would only be efficient at its rated hull speed.
Another example is disclosed in the U.S. Pat. No. 5,954,009 (the '009 patent), which teaches the application of a “wake reflector system” disposed about a traditional hull shape to contain the bow, stern, and transverse waves. The specification claims that the system is applicable to both surface vessels and submarines. Like the '687 patent, this patent does not take waves generated in the downward direction into account, and it does not attempt to reduce the formation of the waves themselves. The waves are only contained until the vessel has traveled clear of the zone of their immediate effect.
Icebreakers are specialized vessels that typically use their weight to ride on top of ice to break it. Icebreakers typically leave the resulting channel full of broken ice that is easy to re-freeze and block an ice-bound passage again. In addition, icebreakers of the prior art are prone to propeller damage due the presence of ice pieces floating at the surface.
What is needed, therefore, is a vessel hull that does not create bow, stern, or transverse waves when moving through the water, and that can break and clear ice from a channel without endangering a vessel's propulsion means.